sqlite3_open：“无法打开数据库文件”

执行rc = sqlite3_open（“test.db”，＆db）时，我“无法打开数据库文件”; ??

sqlite3 *db; // sqlite3 db struct char *zErrMsg = 0; int rc; // Open the test.db file rc = sqlite3_open("test.db", &db); // <-- creates DB if not found ?? if( rc ){ // failed fprintf(stderr, "ERROR: Can't open database: %s\n", sqlite3_errmsg(db)); } 

Answer 1

如果数据库尚不存在， sqlite3_open将返回错误。 要创建数据库（如果该数据库尚不存在）， SQLITE_OPEN_CREATE sqlite3_open_v2与SQLITE_OPEN_CREATE和SQLITE_OPEN_READWRITE标志一起使用（ 两者都是必需的 ）：

 rc = sqlite3_open_v2(/* DB Path */, &db, SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE, NULL); 

参考

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要查找/* DB PATH */ ，您需要将文件名基于文档目录：

 - (NSString *) applicationDocumentsDirectory { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *basePath = ([paths count] > 0) ? [paths objectAtIndex:0] : nil; return basePath; } 

您可以使用此便捷方法将文档路径与数据库名称组合在一起：

 NSString *documents = [self applicationDocumentsDirectory]; NSString *dbPath = [documents stringByAppendingPathComponent:@"test.db"]; rc = sqlite3_open_v2([dbPath UTF8String], &db, SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE, NULL); 

Answer 2

 #define SQLITE_OK 0 sqlite3 *db; char *zErrMsg=0; if(sqlite3_open("demo.db", &db) == SQLITE_OK) { if(sqlite3_exec(db, "select * from Users", callback, 0, &zErrMsg) == SQLITE_OK) msgbox1("success"); sqlite3_close(db); } else msgbox1("failure"); 

这是我使用的示例代码;